Combining Long-Term Data and Ecological Modeling to Assess Sensitivity of Coastal River Otters to Climate Change

Scope of Work:

Catastrophic oil spills such as the Deepwater Horizon, Exxon Valdez, or the Esso Bernicia are rare, but their ecological impacts can last for decades. The acute and lingering chronic effects of such oil spills have been well studied, demonstrating that long-term monitoring of ecosystems affected by such ecological catastrophes is necessary for future management recommendations. In the over-two-decades since the Exxon Valdez Oil Spill (EVOS), Alaska coastal ecosystems have shown strong signs of recovery. One of the first species to recover from EVOS was the North American river otter (Lontra canadensis). The long-term, multi-agency, studies of river otters following EVOS highlighted their susceptibility to environmental catastrophes, their sensitivity to climate-induced changes in fish communities, and their key role in linking aquatic and terrestrial ecosystems at the land-margin. These attributes led to the identification of river otters as a sentinel species and a ‘vital sign’ of Alaska coastal ecosystems. River otters are predominantly fish predators that use terrestrial sites as latrines for social activity and intra specific communication. Through these activities river otters play a significant role in the transfer of nutrients from sea to land. The social structure and abundance of river otters are dependent on the availability of forage and demersal fishes. A recently developed spatially explicit individual-based model predicts a shift in social behavior and population declines of river otters in response to reductions in forage fish abundance. Thus, long-term monitoring of river otter sociality, diet composition, and abundance in various locations along the Alaska coast provides insight into ecosystem recovery from EVOS and its responses to the threat of climate change

The scientific advances in understanding river otter ecology were complemented by intensive demographic and genetic surveys, conducted in various sites of coastal Alaska. The magnitude and diversity of the research efforts over the past two decades yielded a wealth of data that is currently deposited in various formats maintained by various agencies. In order to establish valid monitoring program for river otters, a systematic inventory of the diverse types of data, and a subsequent synthetic analysis will be required.